The invention relates to a holding device for door closers comprising a support member, which is axially displaceably guided in a reception chamber of the housing of the door closer, which is actuated in dependence on the movement of the closer shaft and which is formed, at least in part, as a hollow cylinder; an abutment member which is arranged in the reception chamber coaxial to the support member, with an oblique surface of a cone facing the abutment member and with the cone being biased towards the abutment member by a spring braced against the support member; and at least one locking element located between the cone and the abutment member, with the locking element being capable of being changed over between a release position in which it is located in the hollow cylindrical section of the support member and a blocking position in which it is disposed between an oblique end face of the support member, the cone and the abutment member.
A holding device of this kind is known from DE-PS 31 51 498. This known holding device is a purely mechanical device by means of which a door can be held at a specific angle of opening and in which no controlled release of the holding function is provided. If, in this known arrangement, the door is to be released then excess pressure must be exerted on the door, i.e. a force must be exerted on the door in the closing direction which is larger than the retaining force acting in the holding position, so that the holding arrangement is released and the door is returned to the closed position by the door closer.
A hydraulic holding device for door closers is known from DE-OS 25 23 154 in which the holding of the doors takes place at any desired angle or opening by preventing, of means of a valve, in particular an electromagnetically controlled valve, the flow of a hydraulic medium out of a pressure chamber which increases in size during the opening movement and decreases in size during the closing movement. A disadvantage of these known solutions is firstly that the doors can remain open that any desired angle, for example between 80.degree. and 180.degree., although in practice the door should always be opened as far as possible and should remain held there. A typical example of this is a wall which extends at right angles to the door wherein, in the normal case, the opened doors should always contact this wall and should also remain there. Furthermore, it is a substantial disadvantage of the known hydraulic holding devices that creeping of the door in the direction of closing takes place, even with the smallest hydraulic leaks, which can mean that the door stands away from the wall only a few hours after it has been moved into the opened position, and no longer adopts the desired fully opened position.
The principle object underlying the present invention is to provide a holding device for door closers which makes it possible to hold the door open, in particular only at a predetermined angle of opening, and to maintain the selected opened position without change over periods of time which can be as long as desired, and which is electrically controllable in order to release the holding device. Furthermore, the constructional volume of this holding device should be kept as small as possible and the current consumption of the closer should be kept as low as possible.